In a system including guided vehicles such as overhead traveling vehicles, a controller assigns a transportation command to the guided vehicle for allowing the guided vehicle to travel to the destination in the transportation command. In an intersection such as a branch point or a merge point, the guided vehicle requests blocking of the intersection to the controller. After the guided vehicle passes the intersection, the guided vehicle requests cancel of blocking to the controller (Japanese Patent No. 3367485). If the transportation command is changed in the middle of executing the command, and the destination is changed as a result of the change of the transportation command, the guided vehicle stops temporarily, and the travel route to the new destination is calculated. Then, the guided vehicle starts traveling again. However, if the guided vehicle stops, the transportation efficiency is lowered. Further, in the case where a plurality of guided vehicles are traveling successively with a predetermined distance between the vehicles, the following vehicles also need to stop disadvantageously.